In prior inrush current limiting and overcurrent circuits when the current flowing from a supply to a power converter is at its maximum value the power dissipated in the power converter is at a very high level. With the input current control circuit of the present invention, power dissipation during overcurrent is at a relatively low level, and less than the maximum power dissipation that is input current control circuit occurs. In addition the input current control circuit of the present invention does not use feedback, which eliminates oscillation, which is possible in some prior switching regulators.
The following references are related to power switching regulators:
1. D. Newton, "High Speed Electronic Circuit Breaker", TMOS Power FET design ideas, Motorola, 1985.
2. J. C. Sturman, "Design of high voltage, high power, solid-state, remote power controllers for aerospace applications", Proceedings of the ESA, PESC, 1985.
3. C. Neveu and D. Levins, "Design and development of a current limited solid stated hybrid switch", Proceedings of ESA PESC, 1985.
4. R. Adair, "Limiting inrush current to a switching power supply improves reliability, efficiency", EDN, May 20, 1980.
In reference 1, a Field-effect Transistor (FET) is used as a circuit breaker, but inrush current limiting and automatic reset are not provided. In reference 2, as well as reference 3, the circuits described are current limited switches that may be closed or opened from a remote location. These designs are similar to a solid-state relay with the added feature that the relay will open when the current becomes too high, but these circuits also do not provide inrush current limiting. In reference 2, multiple FETs are used, but current sharing, as employed in the present invention is not utilized. Reference 4 refers to several standard inrush current limit techniques.